Contact Structure of Semiconductor Device and Method for Fabricating the Same

Abstract

A method for fabricating a contact of a semiconductor device includes the steps of forming a dielectric layer having a contact hole on a semiconductor substrate, forming an outgassing barrier layer comprising a poly-silicon layer to cover at least inner walls of the contact hole in order to prevent undesired outgassing from the dielectric layer, and depositing an aluminum layer on the outgassing barrier layer. The contact structure of the semiconductor device includes the aluminum layer filled in the contact layer formed on the semiconductor substrate, and the outgassing barrier layer formed under the aluminum layer to prevent outgassing from the dielectric layer. A fine contact can be formed along with the aluminum layer, thereby realizing the contact structure of a lower contact resistance. As a result, it is possible to realize stabilization of an overall contact resistance of the semiconductor device.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a semiconductor device and, more particularly, to a contact structure of a semiconductor device using an aluminum layer, and a method for fabricating the same. [0003] 2. Description of the Related Art [0004] Reduction in design rule of a semiconductor device has resulted in gradual deterioration of a contact hole filling properties. Accordingly, to effectively fill a contact hole of a high aspect ratio with a fine critical dimension, a method for forming a tungsten contact has been introduced, which employs a chemical vapor deposition (CVD) process to deposit tungsten. [0005] Meanwhile, as an operating speed of a higher level, for example, an operating speed of 667 MHz or more has been required for semiconductor devices, for example, graphic memory devices, reduction of contact resistance has been also required. Because tungsten has a relatively high specific resistance of about 20 μ...

AI Technical Summary

Benefits of technology

[0013] According to one aspect of the present invention, a method for fabricating a contact of a semiconductor device includes forming a dielectric layer having a contact hole on a semiconductor substrate; forming an outgassing barrier layer containing silicon (Si) to prevent discharge of gas from the dielectric layer; forming a metal wetting layer on the barrier layer; and depositing an aluminum layer on the wetting layer.

[0020] According to another aspect of the present invention, a method for fabricating a contact of a semiconductor device includes forming a dielectric layer having a contact hole on a semiconductor substrate; forming an outgassing barrier layer comprising a poly-silicon layer to cover at least inner walls of the contact hole in order to prevent undesired gas from being discharge from the dielectric layer; and depositing an aluminum layer on the outgassing barrier layer.

[0026] According to the present invention, the method for fabricating the aluminum contact structure and the contact structure formed thereby can prevent deposition property from being deteriorated due to the outgassing when forming the contact by means of the outgassing barrier layer which provides an excellent coverage property for the walls of the contact hole.

Problems solved by technology

Reduction in design rule of a semiconductor device has resulted in gradual deterioration of a contact hole filling properties.

However, when filling a contact hole with an aluminum layer, gases generated from an inter-dielectric layer constituting a side wall of the contact obstruct deposition of the aluminum layer, thereby deteriorating step coverage of the aluminum layer.

The discharged gases can serve as elements of obstructing deposition of the Al layer, and lead to deterioration in filling property of the Al layer in the contact hole 25.

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